Bubb says ministers have not filled the vacuum left by the billions of pounds of spending cuts. Photograph: John Robertson/Alamy

The government's radical plans to cut billions from public services are in danger of creating a "forgotten Britain" where the plight of "whole swaths of society is getting worse but is invisible to the rest of us", according to Britain's charity chiefs.

He says charities have spoken to him about their "concern that public attitudes are hardening, with greater suspicion of those who rely on publicly funded support, be they disabled, mentally ill or unlucky enough to be raised as a child in a 'feckless' family".

Bubb says Britain faces a "growing gap between social need in this country and public resources available to spend on it" as unprecedented spending cuts bite hard – costing charities, who deal with those on the fringes of society, "£5bn by the end of the current spending review period".

The charity leader, who has advised the government on health reforms, also warns of a democracy deficit. Although central government mandates the cuts, he says many decisions are made locally – without effective scrutiny, despite the devastating human consequences.

This at a time when only 1 in 3 eligible voters bothered to vote in the local elections this month, says Bubb. In the inner cities, turnout was much lower, with just 8% turnout reported in some wards. "Local media is weak, only a third of us vote in local elections, and the quangos like the Audit Commission that once interrogated local decisions have been pared back or abolished," he says.

"The result is that we are in danger of creating, in the midst of one of the richest countries in the world, a 'forgotten Britain' – swaths of our society whose plight is getting worse ... The homeless, victims of domestic violence, those with mental health problems, the elderly and alone, children in broken homes – the support for these people looks likely to be eroded over the next decade, without the nation they are part of appearing to notice or care."

Bubb says the problem has been a timidity over "genuine public service reform", citing the delay over producing a workable and funded social care white paper in the Queen's speech as an example of ministerial dithering.

He argues that ministers have simply not filled the vacuum created bybillions of pounds of spending cuts: "There is a brutal logic at play: if you remove billions from public services and do not reform them, the people who rely on them suffer. As one [charity leader] said to me, 'spending less is not necessarily a disaster. But spending less and trying to do things the same way is'."

This means thatHe feels charities that operate "below the radar" of the state, reaching some of the hardest cases, find no support when the funding dries up.

Freedom from Torture, a charity that helps refugees who have survived horrendous physical and mental abuse, says the experiences of Gabir, an Iraqi who fled to Britain more than six years ago, are typical. Although given leave to remain and unable to walk, Gabir was denied disability benefits for 11 months and faces eviction after the government capped housing benefit – losing his spot on the housing list after six years and his ties to the local NHS.

Freedom from Torture's chief executive, Keith Best, said: "Cuts to welfare and housing benefits are leaving people unable to cope and the drastic reduction in government funding to frontline refugee services has left many with nowhere to turn for advice and support – we see people every day who are destitute and street homeless."

A spokesperson for the Cabinet Office said, "As yesterday's Queen's speech highlighted, we are putting families front and centre of our national life, with unprecedented support for parents and the biggest reform for 30 years of support for children with special needs or disabilities."

"The government is taking the tough, long-term decisions to restore our country to strength. We are dealing with the deficit, rebalancing our economy and building a society that rewards people who work hard and do the right thing, while protecting the vulnerable."